Apparatus for burning finely-divided coal



Jul 9 1929, w. B. CHAPMAN 1.719.87

APPARATUS FOR BURNING FINELY DIYIDED COAL Filed Aug. 18, 1925 3 Sheets-Sheet 1 MM RCLM July 9, 1929., w, CHAPMAN LTIQBTIW APPARATUS FOR BURNING FINELY DIVIDED COAL Filed Aug. 18, 1923 3 Sheets-Sheet 2 DUST PIT SLAG PIT f July w. B" CHAPMAN WWW;

APPARATUS FOR BURNING FINELY D IVIDED COAL Filed Aug. 18, 1923 3 Sheets-Sheet 5 l tillltli mm-mmimmam "llll'lliliiltilllltlltll 1H. on l l'liil ill 'll'dl t lll'mltlttllt'hl lllllllll "lt llltlll'flfllldillll a enities inea ari en in, mint has tor an object to bringabout the satistactory combustion cl all the fuel particles Without requiring them to be dried and so linely and uniformly pulveriaed as is required tor eaisting methods ct burning pulverized coal; necessity is thus obviated oil conditioning; the coal tor the furnace by means oil drying pulverisinp; operations which are notv so expensive as to prevent the general adoption oi finely divided furnace luelo I is an object of the invention to burn linely divided coal. While carried by sus pended in a air column oil such nature as to insure the proper combustion of substantially all. oil the l'uel particles, even though they may vary insize.

il inother purpose o'lt this invention is to provide a suitable boiler setting and boiler so arranged as to malts etlicient use ot' the gases ot combustion produced by an air column of the above nature.

The invention also aims to enable finely divided coal to be burned While carried by or suspended in an air colummyvithout requitting preheating the air making up such col inn, although it is to be understood that pre eated air may be employed if desired.

Further objects and advantages oi the invention Will. be in part obvious and in part specifically pointed out in the description hereiuatter contained, Which, talrcn in connection With the accompanying drawings, discloses the invention as applied to certain ditlerent types at boiler; such embodiments of the invention, however, are to be considered as merely illustrative of its principles,

in the drawings:

Figs. 1, 2 and 3 are vertical sectional views showing different types of boilers adapted to be operated in accordance with the invention, also top teed, mid teed and under teed types of tuel teed.

lln accordance with the present invention l provide an upwardly directed column ct air traveling" at a sullicient velocity to sup port or carry in suspension finely divided coal particles, and finely divided coal is fed into such column or carried along therewith, vvhereby the fuel particles may be burned present invention the which yvhile so supported or carried in suspension. the column oil air moves at a velocity which decreases the air travels upwardly, Where by the lighter and more quielrly consumed l'fuel particles Will be supported and burned in the stone ot combustion Which exists at the upper portion oil the column, and whereby the h Jl ltlt l su easily ignited fuel par icles, which tend to pass downwardly thro i and out of the none of combustion, rained therein by reason of the ocity oi? the air in the lovvcr porcoluuin. llo burn eight- Vnipleit is only necessary to t veloclty oi the air at the or entrance end of the air column to hold the largest :lucl particles in suspension, Which particles in an ordinary furnace Would tall to the bottom before their coinbastion was completed. According to the velocity of the heavier particles, Which, Would tend naturally to in crease as they tall, is arrested by the increased velocity of the air blast encountered, and the particles therefor become suspended in the air column. Q

In other Words, it the l'uel particles drop further into the air column, their velocity oi" fall tends to increase, butthis greater tend-- ency of the particles to tall is counteracted by the greater velocity ot the air column exists in the lovver portion thereol. It desired, the air which forms the above column may be preheated in any suitable manner, but in installations Where preheated air is not desired to be used, the column may consist of air at ordinary temperature, since substantially thrown into the cone of combustion and all the loci particles may be till ltl

maintained therein until completely burned by the air column.

Fig. it illustrates the application of the in vention to a simple boiler installation coinprising a drum l having therein longitudinal heated gas passages (not illustrated) lead ing to a due 2 at the forward end ot the drum, and in communication at the rear end thereof with a combustion chamber 3 located below the drum.

The upwardly directed column ct above-mentioned is obtained by teedin air under pressure into an upwardly ared chamber l, from air blast pipe 5 having a nozzle 6 disposed at the lower entrance cud lllli manner as to utilize bf the air is greater.

' tween of chamber 4. The chamber, 4; is of restricted cross sectional area toward its bottom, and merges into the larger combustion chamher-3, constituting in effect an auxiliary or preliminary part of chamber 3. Finely divided coal is fed into the chamber, 4 in an suitable manner, as byfeed worm 7 projec' ticles will be floated, and a zone of combustion may be formed at this point which Will extend far enough down into chamber 4 to burn the heavier fuel particles which are supported at a lower level where the velocity Combustion may be started for example by inserting a torch into the upper portion of chamber 4, and once the zone of combustion has been formed, the fuel will be burned continuously as it is supported by the air.

I prefer to employ in. connection with the chamber 4, a means for conducting off slag or liquid ash which may be formed; in the embodiment illustrated in Fig. 1, inclined troughs 8 are provided in the wall of the chamber adjacent to its upward end whereby liquid ash may be trapped in such troughs and conducted to an exterior chamber 9, which is shown as provided with a door 10. The lower portion of chamber 4: is also shOWn as associated with a pit 11 from which access may be had to a trap 12 disposed beneath the chamber 4: and adapted to receive any refuse which may fall therefrom.

Fig. 2 illustrates the application of the invention to another type of boiler, in such efficiently the heat of the gases of combustion. The boiler shown in Fig. 2 is provided with a drum 13 supported above a set of tubes 14 extending befront and rear headers 15 and 16 respectively. The air chamber 4 is supplied at its lower end with airblast pipe 5* and nozzle t) similar to the members '5 and 6 previously described, and finely divided coal is suitably fed into the chamber 4. as by feed worm 7. In this instance the gases of combustion pass upwardly fromchamber 4% to the drum 13 and are deflected thereby to flow past the tubes 14: in a downward direction,

and through a dust pit 17 disposed beneath the tubes to an exhaust fine 18. Thus the heated gases instead ofbeing exhausted at the top of the boiler, pass ed at the bottom with the result that only the cooler gases slag used in connection therewith.

which have given up as much heat as possible in passing through the boiler, are withdrawn.

In the embodiment of the invention illustrated in Fig. 2 preferably means is prov vided to prevent the molten ash from col "lecting unduly around the walls of the chamber 4, "suchas the overhanging ledges 19 on the walls of the chamber, from which the may drop into a chamber 20. l The inclined wall 21 of chamber'4 furthermore is illustrated as provided with gaps 22 through which the slag may drop into a slag pit 23.

Figs. 1 and-2 show the invention as applied to certain types of boilers; In Fig. 3 I have illustrated the invention as combined with a type of boiler specially adapted to be According to this figure a boiler is employed having a drum 24 suitably supported within walls 25 and provided with an annular set of tubes 26 leading downwardly to an annular header 2?. A chamber 4 is disposed centrally beheath the drum 24: so that the gases of combustion rise upwardly in the chamber onclosed by the set of tubes 26 and over the top of an annular baffle 28, until they are deflected by drum-24E to flow downwardly past the set of tubes 26-and header 27 to an annular gathering chamber 29 at the bottom of the furnace and communicating with an exhaust flue 30. v

The chamber 4' is provided with gaps 22 to permit the slag to drop from its walls into a slag pit, the chamber 4e being frusto conical in shape as illustrated so that the gaps 22 may extend entirely around its walls.

According to Fig. 3 furthermore air is fed into the bottom of chamber 4" through a blast pipe 5 into which finely divided coal is also fed, the coal being projected upwardly into chamber 43 by the air, through or by a port 31 into which the pipe 5 leads. The apparatus of Fig. 3 is arranged to automatically control the area of opening through which the compressed air and finely divided coal is fed, according to the air pressure of the feeds; as shown, a regulator member 32 is guided by a rod 33 slidahlc in a spider 34 disposed in port 81, in such posh tion that the member 32 tends to fall to a position in which it obstructs the passage of the air and fuel into conduit 4;"; the air pressure tends to lift the regulator member 32 and thus increase the area of the feed opening; the resultant area of opening therefore depends upon the balance of the above two features whereby when the apparatus is operated at a fraction of its full capacity a restricted area of feed opening maintains an air-velocity which will be sufiicicnt to lift and support the coal as desired; and if a cer tain amount of coal should pass into the central region of the chamber where it will not be adequately supported, the lCcfTIlllllO lator will deflect it again into the annular 7 feed opening surrounding the regulator, where the coal will be again projected up wardly. i

In some instances the walls of the chamber 4 may converge to form an inlet opening at its bottom which is restricted in size both longitudinally and laterally of the furnace, resultingina funnel-shaped chamber; and in other instances two of the side walls of such chamber may be parallel and spaced apart approximately a distance equal to the "width of the furnace, in which case the inlet opening at the bottom of the chamber will be elongated or slotlike in cross section. In

the latter casethe pipe 6 may be omitted and the air merely pro ected into the chamber 12 through the pipe 5, after'which the air will pass upwardly into the chamber 4 through the slotlike inlet opening-thereof.

While certain embodiments of theinvention have been disclosed, it will be obvious that man changes may 'be made therein without e arting from its principles, as defined in tlie appended claims.

I claimz- 1. An apparatus for burning finely divided solid fuel comprising an upwardly directed chamber, means for conducting air under pressure into the lower portion of such c amber, said apparatus including means whereby finely divided solid fuel may be fed into said chamber, and means for conductin liquid ash from off points on the side wall ofsuchchamber which are without the direct range of action of the air blast.

2. An apparatus for burning finely d1 vided solid fuel comprising an upwardly directed chamberof cross sectional area increasing toward the top thereof, means for conductin air under 'ressure into the lower portion 0 such 'cham er, said a paratus in cluding means whereby finely ivided solid fuel may be fed into such chamber, and means for conducting liquid ash from on points on the side wall of such chamber which are without the direct range of action of the air blast.

3. The combination set forth in claim 2, wherein the wall of the chamber is provided with a gap adapted to permit liquid ash to drop from oil such wall.

4. An apparatus for burning finely divided solid fuel comprising an upwardly directed chamber of restricted cross sectional area toward its bottom and provided with a restricted bottom opening, means for admitting fuelto said chamber and for conducting air under ressure' into the .lower portion of such chamber to float the finely divided fuel, means disposed in the hot portion of said chamber for drawing ofi' liquid ash from the Walls thereof, a combustion chamberdisposed adjacent the upper portion of said first mentioned chamber, said apparatus including a boiler having heating tubes and passages adapted to conductthe gases of combustion from the upper portion of said first mentioned chamber past said tubes and finally in a downward direction whereby said gases are exhausted at a low point in their travel through the boiler.

5. The combination set forth in claim 4, together with a gathering chamber disposed adjacent the bottoms of the tubes, and wherein the heating tubes are disposed about the upper portion of the first mentioned chamber in claim 4, to enclose the gases of combustion projected upwardly from the chamber, and said passages conducting the gases downwardly through an annular path past the tubes to said gathering chamber. V

6. An apparatus for burning finely divided solid fuel comprising an upwardl directed chamber of restricted cross sectlonal area toward its bottom and provided with a bottom opening, means for conducting air under pressure upwardl through said opening, said apparatus inc uding means whereby finelydivided solid fuelmay. be fed into such chamber and means for automatically controlling the cross sectional area of the air column passing upwardly into said chamber in accordance with the amount of air being fed therethrough.

I 7. The combination set forth in claim 6, wherein the last-mentioned means is constituted by a floating regulator member in thefor distributing the force of the air blast toward'the walls of such conduit.

\ 9. An apparatus for burning finely divided solid fuel, comprising an upwardly directed chamber of cross sectional area which is relatively small at the bottom and greater toward the top thereof, said apparatus including means whereby finely divided solid fuel may be fed into such chamber, and means for conducting air under pressure into the lower part of such chamber and for intensifying the air blast toward the lower portion of the walls of the chamber.

10. An apparatus for burning finely divided solid fuel, comprising an upwardly directed chamber of cross sectional area increasing toward the top thereof, means for conducting air under pressure into the lower part of such chamber, said apparatus including means whereby finely divided solid fuel may be fed into such chamber, and a deflector member located in the lower portion of such chamber and acting to deflect the air blast toward the lower portions of the walls of the chamber.

11. An apparatus for burning finely divided solid fuel comprising an upwardly directed chamber of restricted cross sectional area at its bottom, and also provided with an opening of restricted size at its bottom, means for conducting air under pressure upwardly through said opening into said chamber, said apparatus including means whereby finely divided solid fuel may be fed into said chamber to be supported by the upwardly moving column of air therein, and means adjacent the said bottom opening tor altering the cross sectional areaof the air column which moves upwardly into the chamber.

12. An apparatus for burning finely divided solid fuel in suspension, comprising a combustion chamber, restricted at its base to form a relatively small fuel and air feed opening at the bottom, a boiler having tubes surrounding said combustion chamber, said boiler also over-lying the top of the combustion chamber, means associated with said feed opening for distributing the fuel and air fed in through said opening toward the side Walls of said combustion chamber whereby the products of combustion are directed upward toward the tubes in said combustion chamber, said apparatus being provided with an annular passageway enclosing said combustion chamber and including said tubes to lead the products of combustion downwardly along said tubes, and an outlet flue for the spent gases disposed adjacent the bottoms of the tubes.

In testimony that I claim the foregoing, I have hereunto set my hand this 15th day of August, 1923.

WILLIAM B. CHAPMAN. 

